Classical microscopes with purely optical magnification may use a very large optical lever for achieving large image distances at short camera-to-subject distances. Said so-called large optical levers result in long lens tube lengths and thus in long constructional lengths of the microscopes. Known conventional microscope structures may have heights ranging from 25 to 50 cm. As magnification increases, the observable object field in classical microscopes becomes smaller. Classical microscopes are still optical-mechanical precision instruments that are corrected with a lot of effort and are therefore expensive to manufacture.
Due to their small pixel sizes, new digital image sensors now for the first time enable photographing of small object details, depending on the pixel size at optical 1:1 imaging, that is, image field=object field, or at only very small optical magnification, said technology being referred to as digital macrophotography. A disadvantage of this technique is that when the constructional length of a corresponding objective is reduced and in the event of large object dimensions, oblique passage of the light results at the edge of the image field through the macro objective and/or the one lens channel and, thus, extremely strong aberrations result at the edge of the image field (so called off-axis aberrations), whereby the image quality is highly effected or expensive correction may need to be performed.
To achieve low constructional heights of digital imaging systems, a concept of utilizing several optical channels continues to exist. Said so called array approach enables parallel transmission of adjacent object parts into neighboring image parts by periodically adjacently arranged, identical objectives and/or imaging channels which do not or only slightly influence one another. As a result, image transmission is essentially performed perpendicularly again (except for the small angles of field within the individual channels), that is, as opposed to the one-channel variants, no oblique passage of the light will result at the edge of the image field, the object field scaling with the image sensor size and/or the number of channels used, and the constructional length being independent thereof. One disadvantage of this array approach is that due to the array geometry of the arrangement, artifacts in the image may possibly result. Said artifacts may translate, for example, into modulation of the resolution, brightness or magnification, depending on the period of the array. A further problem is optical crosstalk between the different channels, the prevention of which is critical. Due to said utilization of several channels, both the object field and the image field are subdivided into several partial object fields and partial image fields, depending on the number of channels. To this end, in the array approach described, there are different variants of combining object field joint and image field joint, i.e. of assembling the partial object fields and partial image fields.
In addition, variants wherein several channel contribute to the formation of an image point (pixel), which thus have a higher level of luminosity, differ from variants wherein only one channel contributes to the formation of the image point, which have a higher resolution.
In summary, one may state that in known conventional technology, there is no concept which combines imaging of laterally extended close objects, i.e. comprising a small distance of the object from an imaging system, at a high level of image quality with a small constructional height of the imaging system.